1. Field
This disclosure is generally related to performing data and service migration in a content delivery network. More specifically, this disclosure is related to using the content-centric network (CCN) architecture to perform server handoff.
2. Related Art
Hosted services are typically implemented using one or more servers that may be deployed as a hierarchical and distributed system that is designed to provide reliable and scalable access to a service. The servers may be broken down into a set of content servers that host the supported service or its underlying components, and a set of edge servers that each provides the service to a set of client devices or serve as a front end to clients to coordinate access and control. Oftentimes, a service may be deployed across multiple data centers that are distributed across a wide geographical region, for example, to minimize network latency to any client device. One such example of an available service is a Content Distribution Network (CDN).
Over time, it is typical for the request load to change across servers. An individual server may experience a heavy request load due to a spike in requests from a plurality of users, or due to an uneven placement of content across the edge servers. If the load becomes too heavy for a server or underlying service component, the server's response to a user's request can degrade significantly, which can quickly change a user's perceived performance of the service as a whole.
System administrators typically attempt to ensure that the service is reliable for all users by ensuring that no single edge server or service component becomes over utilized. This may require, for example, configuring the system to perform load balancing across the set of servers. The system administrator may also need to migrate data and/or functions between servers, such as when a given edge server has become over utilized.
Unfortunately, performing load balancing across edge servers is a complicated task that needs to be performed carefully to prevent interrupting service to a client device. Existing systems typically perform load balancing across servers by assigning each new client device request or service function to a particular server, and configuring the requesting device to communicate with the server to receive any other data packets for the current session.
However, this configuration requires the client device to continue communicating with the same server until the current session is complete, even if this server becomes over utilized. For example, when the CDN system copies content over to a new server, the CDN system configures some or all client devices to direct any new download requests to this new server. However, the CDN system may allow the ongoing requests to continue downloading their data streams from the previous server. This, of course, causes the previous server to remain overloaded until a sufficient number of clients have finished downloading their data streams, which forces these clients to continue experiencing performance thrashing for an extended time period after the new server has been brought on line.